EP2166915B1 - Domestic appliance with a self-diagnosing door lock position detection device - Google Patents

Description

The invention relates to a household appliance according to the preamble of patent claim 1.

The detection of the door lock position in a household appliance is necessary to ensure safe operation of the household appliance. For example. With a dishwasher, the circulation pump is stopped when the door is no longer closed. This scalding should be avoided by spraying out water.

It is known to detect the door lock position by means of a reed switch. The reed switch comprises arranged in a shelter, magnetizable switch contacts, which are brought by an external permanent magnet in a closed position or open position. The permanent magnet is arranged on a movable closing part of the door lock. Now, when the door lock is opened, the reed switch comes out of the effective range of the permanent magnet. As a result, the reed switch is opened or closed depending on the circuit and a change in the circuit can be detected by a monitoring circuit.

A disadvantage of such reed switches is that malfunctions, for example caused by a short circuit or interruption, are interpreted and evaluated as normal operating states and thus are not recognized.

The GB 2 133 455 A provides a closure device for the door of a household appliance with a pivotable in an open and a closed position forkbolt. This has a fixed latch on the device housing associated fork-shaped end portion and a door inside end portion, which cooperates with a longitudinally guided on a fixed pin, pivotable push rod as a toggle mechanism. On the push rod sits a compression spring which is supported on the one hand against the bolt and on the other hand against the door inner end portion of the fork catch. It is provided in the circuit of the household appliance switch, which at in the open position of the pivoted forked latch actuates the switch via a projection of the push rod and interrupts the circuit of the household appliance.

A household appliance according to the preamble of claim 1 is characterized by EP 1498796 disclosed.

For the actuation of a Türverschlusseinncniung between a closed and an open position, a thermo-actuator is provided. This can move a carriage on which an indicator is provided at a fixed longitudinal position. In this case, the indicator may be formed by a ferromagnetic material. Its position can be detected by means of a Hall sensor.

The invention is therefore based on the object to provide a household appliance with self-diagnostic capability.

The invention relates to a household appliance, in particular water-conducting household appliance, such as. A domestic dishwasher, which has at least one door with which a treatment room of the household appliance can be opened and closed. Furthermore, door position detecting means are provided for detecting an open or closed door position.

The object of the invention is achieved in that the door position detecting means in the open and closed door position a door position corresponding, in particular deviate from zero signal provide. Thus, a signal is available at each position of the door, the presence of which indicates that the door position detection means are functional.

Preferably, it is provided that provide the door position detecting means in the open and closed door position to each other inverted signals. This allows a particularly simple signal processing for checking the functionality by inverting one of the two signals and subsequent monitoring for deviations out.

It is further provided according to the invention that the door position detection means are connected to a monitoring circuit for function monitoring, so that the functionality of the door position detection means can be tested permanently or also at intervals and an overall self-diagnostic capability is given.

According to the invention, it is provided that the door position detection means are designed for inductive detection. Analog different door positions are assigned different inductances.

According to the invention it is provided that the door position detecting means comprise at least one permanent magnet and a magnetic switch, so that the device has a simple structure.

Furthermore, the invention provides that the magnetic switch is a Hall sensor. In this case, it can be utilized that, with a known input signal, an inverted signal of the input signal is applied to a Hall sensor at its output. With a known input signal can thus be concluded that the expected output signal. If this expected output signal does not occur, either the door lock to be monitored is open or there is a general circuit fault. This makes it easy to integrate an additional security function.

It is preferably provided that the door can be locked by means of a locking device in at least one door position, for example. In the door position, in which the door closes a treatment room of a household appliance. For this purpose, for example, in the case of a domestic dishwasher, a so-called pull-lock can be used, in which only the application of a minimum force is required to open a door, but no keys or the like. In this case, the locking device ensures that the door remains closed even during operation of the household appliance and is not pressed by the pressure prevailing in the treatment chamber internal pressure, which is, for example. Built by heating the air in the treatment room.

In this case, it is preferably provided that the door position detection means is a door lock position detection device. It is therefore not the position of the door, but the position of a closing wedge of a castle recorded. This allows a particularly compact structure, in which both the permanent magnet and the Hall sensor are integrated in a door lock position detection device. Further The permanent magnet and the Hall sensor can be arranged on the door or the housing of the household appliance.

Furthermore, it is preferably provided that by moving the door, in particular by closing, the Hall sensor in the range of action of the permanent magnet can be brought.

In a preferred embodiment it is provided that the monitoring circuit generates a defined signal which is supplied to the Hall sensor and output signals of the Hall sensor are checked for plausibility.

The monitoring circuit according to the invention comprises a comparison circuit which compares output signals of the Hall sensor with a desired signal of the Hall sensor. In the presence of a deviation from an inverted input signal of the Hall sensor can thus be concluded that lack of functionality.

According to the invention, a signal is generated when the output signal of the Hall sensor deviates from the desired signal. This signal can be further processed in a control of a household appliance and trigger various safety measures, such as the switching off of pumps such as the Umwalzpumpe or switching off the heater when the door is not closed. This may be an optical and / or acoustic alarm signal.

In a preferred embodiment of the invention, it is provided that the voltage applied to the input of the Hall sensor defined signal is a pulse signal, for example. With a fixed clock frequency. As a result, the inverted signal at the output of the Hall sensor can be adjusted in a particularly simple manner by simply reversing this pulsed signal.

It is preferably provided that the defined signal is a rectangular signal.

Furthermore, it is preferably provided that the household appliance is a dishwasher.

Finally, the invention includes a door lock position detection device for a household appliance.

Fig. 1

eine schematische Ansicht einer erfindungsgemäßen Schaltungsanordnung zur Überwachung der Stellung eines Türschlosses, und

Fig. 2

ein Schaltbild der Schaltungsanordnung.

The invention will be explained in more detail in an embodiment with reference to the accompanying drawings. Show it:

Fig. 1

a schematic view of a circuit arrangement according to the invention for monitoring the position of a door lock, and

Fig. 2

a circuit diagram of the circuit arrangement.

Fig. 1 schematically shows a section of a dishwasher 10. The dishwasher 10 has a housing 12 which can be closed by a door 14. The door 14 is hinged to the housing 12 so that it can be opened or closed according to the double arrow 16. Structure and operation of the dishwasher 10 are well known, so that will not be discussed in the context of the present description to this.

The door 14 can be locked by means of a closing device 18 on the housing 12. The closing device 18 comprises a closing wedge 20, which can be brought into engagement with a closing latch 22. The latch 22 is disposed on the housing 12 and engages a corresponding opening (not shown) of the door 14 a. The striker 20 is movable by means of an actuator 24. The actuating device 24 comprises a feeler element 26, which can be reached by a recessed grip 28 within the door 14. The probe element 26 is displaceable against the force of a spring element 30, so that via a rotatable ge my known so that in the context of the present description will not be discussed here.

The door 14 can be locked by means of a closing device 18 on the housing 12. The closing device 18 comprises a closing wedge 20, which can be brought into engagement with a closing latch 22. The latch 22 is disposed on the housing 12 and engages a corresponding opening (not shown) of the door 14 a. The striker 20 is movable by means of an actuator 24. The actuating device 24 comprises a feeler element 26, which can be reached by a recessed grip 28 within the door 14. The probe element 26 is displaceable against the force of a spring element 30, so that via a rotatably mounted cantilever 32 of the locking wedge 20 out of engagement with the latch 22 can be brought or by pressing the door 14 automatically by the force of the spring element 30 into engagement with the latch 22nd can be brought. The schematic structure of the locking device 18 shown here is merely exemplary. Any other suitable embodiment is possible.

Furthermore, a door lock position detecting device 64 is provided which comprises at least one permanent magnet 34 and a Hall sensor 36 serving as a magnetic switch. In this case, the permanent magnet 34 is arranged on the door 14, while the Hall sensor 36 is fixedly secured to the housing 12.

When the closing device 18 is opened, the closing wedge 20 experiences a movement. On the closing wedge 20, the permanent magnet 34 is arranged, the effective range is located in the detection range of the Hall sensor 36 with the door 14 closed. The Hall sensor 36 is connected to a monitoring circuit 38. Here, by means of connecting lines 62, an input 40 of the Hall sensor 36 is connected to an output 42 of the monitoring circuit and an output 44 of the Hall sensor 36 to an input 46 of the monitoring circuit 38. A switching output 48 of the monitoring circuit 38 is connected to a switching element 50 of a supply voltage circuit 52 for a circulation pump motor 54 of the dishwasher 10.

• Während des bestimmungsgemäßen Einsatzes des Geschirrspülers 10 ist die Tür 14 verschlossen. Das heißt, der Schließkeil 20 greift in die Schließfalle 22 ein, so dass der Permanentmagnet 34 eine definierte Position in Bezug auf den Hallsensor 36 einnimmt. Wird nun während des Betriebes des Geschirrspülers 10 die Betätigungseinrichtung 24 vershentlich betätigt, verändert sich die Lage des Permanentmagneten 34 in Bezug auf den Hallsensor 36. Eine hiermit einhergehende Änderung der Hallspannung des Hallsensors 36 wird durch die Überwachungsschaltung 38 erfasst und ein Ausschaltsignal für den Umwälzpumpenmotor 54 generiert. Dies geschieht durch Ansteuerung des Schaltelements 50.

In the Fig. 1 The circuit arrangement shown has the following function:

• During the intended use of the dishwasher 10, the door 14 is closed. That is, the striker 20 engages the latch 22 so that the permanent magnet 34 occupies a defined position with respect to the Hall sensor 36. Will now during operation of the dishwasher 10, the actuator 24 accidentally actuated, the position of the permanent magnet 34 changes with respect to the Hall sensor 36. A concomitant change in the Hall voltage of the Hall sensor 36 is detected by the monitoring circuit 38 and a turn-off signal for the circulation pump motor 54 is generated. This is done by driving the switching element 50.

The monitoring circuit 38 simultaneously includes a self-monitoring of the Hall sensor 36. For this purpose, at the output 42 of the monitoring circuit 38 to a defined signal at which the Hall sensor 36 is fed via its input 40. At the output 44 is then an inverted signal of this input signal, via the input 46th the monitoring circuit 38 is supplied. The monitoring circuit 38 can compare the actual input signal on the monitoring circuit 38 with the expected desired input signal by means of a comparison circuit 56. In the event of a deviation, either a malfunction of the Hall sensor 36 or an interruption or a short circuit in the connecting lines 62 between the monitoring circuit 38 and the Hall sensor 36 is present.

Based on Fig. 2 the comparison circuit 56 will be explained. The comparator circuit 56, on the one hand, generates the output signal 58 present at the output 42 of the monitoring circuit 38 and, on the other hand, receives the input signal 60 present at the input 46 of the monitoring circuit 38. The output signal 58 is fed to the output 42 via a voltage divider of the resistors R1 and R2 and is thus applied Input 40 of the Hall sensor 36 at. Via an input transistor T1 whose collector is connected to the input 40, this output signal 58 is fed to the sensitive chip 55 of the Hall sensor 36.

At the output 44 of the Hall sensor 36 is then the inverted input signal, which is supplied via the input 46 of the monitoring circuit 38 as a signal 60 of the comparison circuit 56.

In the example shown, the output signal 58 of the monitoring circuit 38 is a rectangular signal with a predetermined clock frequency. The signal 60 is then - in the correct mode - exactly the inverted signal of the signal 58th That is, when the signal 58 has the level LOW, the signal 60 has the level HIGH, and when the signal 58 has the level HIGH, has Signal 60 the level LOW.

By means of the comparison circuit 56, the signal 60 can now be evaluated in accordance with the signal 58 as to whether this actual signal 60 corresponds to the expected desired signal. If there is a deviation between the expected signal and the actual signal 60, the alarm signal for interrupting the supply voltage circuit 52 is applied via the comparison circuit 56 to the output 48 of the monitoring circuit 38 (FIG. Fig. 1 ) generated.

LIST OF REFERENCE NUMBERS

10

dishwasher

12

casing

14

door

16

Opening or closing the door

18

closing device

20

cotter

22

closing event

24

actuator

26

Button element / button

28

grip

30

spring element

32

cantilever

34

permanent magnet

36

Hall sensor

38

monitoring circuit

40

Input of the Hall sensor

42

Output of the monitoring circuit

44

Output of the Hall sensor

46

Input of the monitoring circuit

48

switching output

50

switching element

52

Supply voltage circuit

54

Pump motor

55

sensitive chip

56

comparison circuit

58

output

60

input

62

interconnectors

64

Door lock position determining means

Claims (9)

1. Domestic appliance (10), particularly water-conducting domestic appliance (10), at least comprising a door (14) and door setting detection means, which are constructed for inductive detection, for detecting an open or closed door setting, wherein the door setting detection means comprises at least one permanent magnet (34) and a Hall sensor (36) and in the case of an open and closed door setting provides a signal, particularly a signal differing from zero, corresponding with the door setting,
   characterised in that

   - the door setting detection means are connected with a monitoring circuit (38), which is constructed at least for checking the functional integrity of the door setting detection means,

   - the monitoring circuit (38) comprises a comparison circuit (56) which compares output signals of the Hall sensor (36) with a target signal of the Hall sensor (36) and generates a signal if the output signals of the Hall sensor (36) differ from the target signal and

   - a control of the domestic appliance (10) processes the signal and in dependence on the signal triggers safety measures in the form of switching-off of a pump, particularly a circulating pump, or of heating means.
2. Domestic appliance according to claim 1, characterised in that the door setting detection means in the case of open and closed door setting provides signals inverted relative to one another.
3. Domestic appliance according to one of the preceding claims, characterised in that the door is lockable in at least one door setting by means of a closing device (18).
4. Domestic appliance according to any one of the preceding claims, characterised in that the door setting detection means is a door lock setting detection device (64).
5. Domestic appliance according to any one of the preceding claims, characterised in that the Hall sensor (36) can be brought into the effective range of the permanent magnet (34) through movement of the door (14).
6. Domestic appliance according to any one of the preceding claims, characterised in that the monitoring circuit (38) generates a presettable signal (52) which is supplied to the Hall sensor (36) and output signals of the Hall sensor (36) are checked for plausibility.
7. Domestic appliance according to claim 6, characterised in that the presettable signal (52) is a pulse signal.
8. Domestic appliance according to one of claims 6 and 7, characterised in that the presettable signal (52) is a square-wave signal.
9. Domestic appliance according to any one of the preceding claims, characterised in that the domestic appliance (10) is a dishwasher.

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